You have almost certainly eaten seaweed, or at least a product derived from seaweed,
without ever realising it, and there are some five to six hundred seaweed species found
around the coasts of the British Isles with about nine thousand found worldwide.

Edible seaweeds are also becoming fashionable and you'll frequently find them referred
to as 'sea vegetables' which is perhaps a more friendly approach to this area of wild
food foraging which for most people is something of a mystery. Yet seaweeds have been
eaten in the British Isles for centuries, were then virtually forgotten, but are now
slowly making a comeback thanks to the renewed interest in wild foods.

Although you will frequently hear it said that all seaweeds in our waters are edible,
some of the more exotic ones contain chemical constituents that are not good for you
in quantity so your safest option is to stick to the tried and tested ones.

Alaria esculenta - Badderlocks
Common in northern parts of the British Isles Alaria esculenta grows up to about 10-12 ft.
in length. It is generally the midrib which is eaten, once the enveloping membrane
has been removed. The young leaflets are also sometimes eaten.

Chondrus crispus - Irish Moss / Carrageen
This is another long-standing and common edible seaweed. A perennial, the fronds grow
up to about 10 inches in length, and provide a jelly-like substance once boiled. Another
seaweed, Mastocarpus stellatus [formerly Gigartina mamillosa], maybe substituted
for Chondrus and is a better geller. Many seaweeds are sources of the carrageenans
and alginates which produce the jelly-like consistency and frequently find their way into
processed food. Hence you have probably eaten seaweed without realising it.

Dilsea carnosa [formerly Iridaea edulis]
This perennial seaweed is not recommended eating these days as it contains suspect compounds;
the name change itself again indicative of the changing face of marine botany as modern
science comes to better understand seaweeds. However this common, perennial, deep red seaweed
was generally eaten raw but sometimes fried. Perhaps keep this one as emergency food only!

Laminaria digitata and saccharina [now Saccharina latissima] -
Tangle / Sweet Tangle The young leaves and stalks of L. digitata may be used as food but
the stalks of this common perennial seaweed become woody with age, the fronds growing up
to six feet in length. As the scientific name of Saccharina latissima suggests this
particular seaweed has a sweetness to it.

Palmaria palmata [formerly Rhodymenia palmata] - Dulse
A dull purplish or brownish-red in colour dulse fronds grow to about 20 inches in length,
though smaller ones are the most tender and not leathery like bigger specimens. This
seaweed may be eaten raw or cooked, or dried and eaten as a snack. In the old days dulse
was often served up alongside potatoes as a dish.

Porphyra umbilicalis and dioica
These two species are stand-ins for Laver when ulva is not available [more on Ulva below].
Both are purplish in colour and slow cooking brings out the best in them.

Ulva lactuca and rigida - Laver
You've probably heard of these common seaweeds even though you might not have set eyes upon
them physically. Ulva is the main constituent of 'Laver bread' - which is not really a
bread at all. These are sheet-like bright or vivid green, delicate, seaweeds.

As they are listed above these seaweeds are in alphabetical order. In botanical terms they are normally
dealt with in regard to their colours, there being three groups identified: the red
group, the olive-brown and the green ones.

While Brits are somewhat lagging behind in their appreciation of edible seaweeds other
cultures around the world embrace them...

The Japanese are into their wakame [Undaria pinnafitida] and kombu [Saccharina
japonica], and also consume Porphyra yezoensis. In Indonesia there's a huge trade
in Euchema cottonii. Worldwide various species of Euchema account for around 70% of
the world's carrageenan supplies. In Hawaii there's a traditional local dish called limu which
can variously be made with the edible seaweeds Gracillaris coronopifolia,
Enteromorpha prolifera, Asparagopsis taxiformis, Grateloupia filicana,
Ulva fasciata, Sargassum echinocarpum and Dictyopteris plagiogramma. Foodies
of the region reckon that lightly roasting Enteromorpha brings out a better taste.

Two important points about harvesting edible seaweeds...
Think about where you are picking from... are there localised sources of pollution?
And harvest just what you need... So if the seaweed is a biennial or perennial don't pull up the
whole plant with its root. Cut the stem cleanly, leaving the root to produce new growth.
For annuals select a few fronds from each plant leaving a good number of specimens behind
intact so that these can reproduce for you to harvest another time.

Two good sources of information on seaweeds are www.seaweed.ie
for a general overview, and AlgaeBase which has a
wealth of technical detail about seasweeds of all types.